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#ifndef __POLKA_H__
#define __POLKA_H__

#include "ContentionManager.hpp"
#include "Polite.hpp"

namespace stm
{
  /**
   * Polka CM, a combination of Polite (bounded randomized exponential
   * backoff) and Karma (priority based on objects opened and attempts to
   * open)
   */
  class Polka : public Polite
  {
    protected:
      // every time we Open something, reset the try counter, increase
      // the karma
      void onOpen()
      {
          priority++;
          tries = 0;
      }

      // query the enemy cm to get its priority, return true if enemy's
      // priority is lower than mine.
      ConflictResolutions shouldAbort(ContentionManager* enemy)
      {
          if (!enemy)
              return AbortOther;
          if ((tries + priority) > enemy->getPriority())
              return AbortOther;
          return Wait;
      }

    public:
      // everything in the Polka ctor is handled by Polite() and
      // ContentionManager()
      Polka() { }

      virtual ConflictResolutions onRAW(ContentionManager* e)
      {
          return shouldAbort(e);
      }
      virtual ConflictResolutions onWAR(ContentionManager* e)
      {
          // per published Polka
          return AbortOther;
      }
      virtual ConflictResolutions onWAW(ContentionManager* e)
      {
          return shouldAbort(e);
      }

      // event methods
      virtual void onReOpen()     { tries = 0; }
      virtual void onOpenRead()   { onOpen(); }
      virtual void onOpenWrite()  { onOpen(); }
  };
} // namespace stm

#endif // __POLKA_H__
